1. Field of the Invention
The present invention relates to an image recording apparatus wherein a plurality of abutment portions abut against a sheet which is being conveyed in a conveyance route.
2. Description of the Related Art
Conventionally, there is known an ink-jet recording apparatus which jets ink droplets toward a sheet from nozzles provided in a recording unit so as to record an image, etc. on the sheet. In the ink-jet recording apparatus, the sheet which is being conveyed in a conveyance route formed inside the apparatus sometimes floats from a member supporting the sheet. Such a floating of the sheet easily occurs particularly at both end portions in the width direction of the sheet. Further, if the floating of the sheet occurs at a position facing the recording unit, the distance between the sheet and the recording unit might be changed and the quality of image, etc. recorded on the sheet might be adversely affected.
In order to solve such a problem, there has been conventionally known an image recording apparatus including a plurality of projections and recesses alternately formed along a conveyance direction in which a sheet is conveyed so that the sheet is moved on the platen in a waved state in which the sheet is waved in a width direction of the sheet orthogonal to the conveyance direction. Specifically, a plurality of ribs which are parallel to the conveyance direction are arranged in a conveyance surface of the platen, and a plurality of abutment portions which abut against the sheet are arranged between the plurality of ribs, respectively.
Provided that the plurality of abutment portions are integrally molded of a synthetic resin, then, in a case that a sheet is conveyed on the platen, the plurality of abutment portions are moved together due to abutment against the sheet. In this configuration, if a sheet which is relatively short in the width direction is conveyed on the platen, some abutment portions which do not abut against the sheet are also moved, which in turn increases load on the sheet. As a result, the conveyance resistance of the sheet is increased, the conveyance precision might be varied (fluctuated), and the load on a motor driving a sheet-conveying roller might be increased.
On the other hand, in a case that the plurality of abutment portions are molded independently of a synthetic resin as separate abutment portions, positions at which the sheet is pressed by the respective abutment portions are varied due to any variation during the molding of the respective abutment portions. For example, in such a case that a plurality of abutment portions having the same shape are arranged in the width direction, the abutment portions having any variations in the molding are arranged and attached in the width direction, and thus a waving shape imparted to the sheet during the conveyance is also varied depending on the apparatuses. In a case that there is any variation in the waving shape of the sheet, the landing positions of the ink (ink droplets) discharged from the recording head onto the sheet are also varied, which in turn might lower the precision or accuracy of a recorded image.
The present teaching has been made in view of the above-described circumstances; an object of the present teaching is to provide an image recording apparatus, in which a plurality of abutment portions abut against a sheet being conveyed in a conveyance route without imparting any excessive load on the sheet and in which any variation in abutment positions of the abutment portions hardly occurs.